Plumbing for a core snapshot with code (currently empty). (flutter/engine#3749)

engine/src/flutter/build/flutter_app.gni

@@ -75,8 +75,12 @@ template("flutter_app") {
       get_label_info(flutter_core_snapshot_label, "target_gen_dir")
   flutter_core_snapshot_vm_data =
       "$flutter_core_snapshot_gen_dir/vm_isolate_snapshot.bin"
+  flutter_core_snapshot_vm_instructions =
+      "$flutter_core_snapshot_gen_dir/vm_snapshot_instructions.bin"
   flutter_core_snapshot_isolate_data =
       "$flutter_core_snapshot_gen_dir/isolate_snapshot.bin"
+  flutter_core_snapshot_isolate_instructions =
+      "$flutter_core_snapshot_gen_dir/isolate_snapshot_instructions.bin"
 
   dot_packages = "$target_gen_dir/$dart_package_name.packages"
   bundle_path = "$target_gen_dir/$bundle_name"
@@ -93,6 +97,10 @@ template("flutter_app") {
 
     inputs = [
       main_dart,
+      flutter_core_snapshot_vm_data,
+      flutter_core_snapshot_vm_instructions,
+      flutter_core_snapshot_isolate_data,
+      flutter_core_snapshot_isolate_instructions,
     ]
 
     outputs = [
@@ -110,8 +118,12 @@ template("flutter_app") {
       rebase_path(gen_snapshot),
       "--vm-snapshot-data",
       rebase_path(flutter_core_snapshot_vm_data),
+      "--vm-snapshot-instructions",
+      rebase_path(flutter_core_snapshot_vm_instructions),
       "--isolate-snapshot-data",
       rebase_path(flutter_core_snapshot_isolate_data),
+      "--isolate-snapshot-instructions",
+      rebase_path(flutter_core_snapshot_isolate_instructions),
       "--main-dart",
       rebase_path(main_dart),
       "--packages",

engine/src/flutter/build/script_snapshot.py

@@ -16,8 +16,12 @@ def main():
                       help='The Flutter snapshotter')
   parser.add_argument('--vm-snapshot-data', type=str, required=True,
                       help='Path to vm_isolate_snapshot.bin')
+  parser.add_argument('--vm-snapshot-instructions', type=str, required=True,
+                      help='Path to vm_isolate_snapshot.bin')
   parser.add_argument('--isolate-snapshot-data', type=str, required=True,
                       help='Path to isolate_snapshot.bin')
+  parser.add_argument('--isolate-snapshot-instructions', type=str, required=True,
+                      help='Path to isolate_snapshot.bin')
   parser.add_argument('--main-dart', type=str, required=True,
                       help='The main.dart file to use')
   parser.add_argument('--packages', type=str, required=True,
@@ -35,11 +39,13 @@ def main():
     args.snapshotter_path,
     '--snapshot_kind=script',
     '--vm_snapshot_data=%s' % args.vm_snapshot_data,
+    '--vm_snapshot_instructions=%s' % args.vm_snapshot_instructions,
     '--isolate_snapshot_data=%s' % args.isolate_snapshot_data,
+    '--isolate_snapshot_instructions=%s' % args.isolate_snapshot_instructions,
     '--packages=%s' % args.packages,
     '--script_snapshot=%s' % args.snapshot,
     '--dependencies=%s' % args.depfile,
-    args.main_dart,
+    args.main_dart
   ]
 
   result = subprocess.call(cmd, cwd=args.root_build_dir)

engine/src/flutter/lib/snapshot/BUILD.gn

@@ -38,11 +38,16 @@ action("generate_snapshot_bin") {
              snapshot_dart,
            ] + dart_ui_files
 
-  vm_isolate_snapshot = "$target_gen_dir/vm_isolate_snapshot.bin"
-  isolate_snapshot = "$target_gen_dir/isolate_snapshot.bin"
+  vm_snapshot_data = "$target_gen_dir/vm_isolate_snapshot.bin"
+  vm_snapshot_instructions = "$target_gen_dir/vm_snapshot_instructions.bin"
+  isolate_snapshot_data = "$target_gen_dir/isolate_snapshot.bin"
+  isolate_snapshot_instructions =
+      "$target_gen_dir/isolate_snapshot_instructions.bin"
   outputs = [
-    vm_isolate_snapshot,
-    isolate_snapshot,
+    vm_snapshot_data,
+    vm_snapshot_instructions,
+    isolate_snapshot_data,
+    isolate_snapshot_instructions,
   ]
 
   rebased_dart_ui_path = rebase_path(dart_ui_path)
@@ -62,9 +67,13 @@ action("generate_snapshot_bin") {
     "--snapshot_kind",
     "core",
     "--vm_output_bin",
-    rebase_path(vm_isolate_snapshot, root_build_dir),
+    rebase_path(vm_snapshot_data, root_build_dir),
+    "--vm_instructions_output_bin",
+    rebase_path(vm_snapshot_instructions, root_build_dir),
     "--isolate_output_bin",
-    rebase_path(isolate_snapshot, root_build_dir),
+    rebase_path(isolate_snapshot_data, root_build_dir),
+    "--isolate_instructions_output_bin",
+    rebase_path(isolate_snapshot_instructions, root_build_dir),
     "--url_mapping=dart:ui,$rebased_dart_ui_path",
   ]
 
@@ -79,40 +88,93 @@ action("generate_snapshot_bin") {
   }
 }
 
-action("generate_snapshot_file") {
+# Generates an assembly file defining a given symbol with the bytes from a
+# binary file. Places the symbol in a text section if 'executable' is true,
+# otherwise places the symbol in a read-only data section.
+template("bin_to_assembly") {
+  assert(defined(invoker.deps), "Must define deps")
+  assert(defined(invoker.input), "Must define input binary file")
+  assert(defined(invoker.output), "Must define output assembly file")
+  assert(defined(invoker.symbol), "Must define symbol name")
+  assert(defined(invoker.executable), "Must define boolean executable")
+
+  action(target_name) {
+    deps = invoker.deps
+    script = "//dart/runtime/tools/bin_to_assembly.py"
+    args = [
+      "--input",
+      rebase_path(invoker.input),
+      "--output",
+      rebase_path(invoker.output),
+      "--symbol_name",
+      invoker.symbol,
+      "--target_os",
+      current_os,
+    ]
+    if (invoker.executable) {
+      args += [ "--executable" ]
+    }
+    inputs = [
+      script,
+      invoker.input,
+    ]
+    outputs = [
+      invoker.output,
+    ]
+  }
+}
+
+bin_to_assembly("vm_snapshot_data_assembly") {
   deps = [
     ":generate_snapshot_bin",
   ]
-  inputs = [
-    "//dart/runtime/tools/create_snapshot_file.py",
-    "snapshot.c.tmpl",
-    "$target_gen_dir/vm_isolate_snapshot.bin",
-    "$target_gen_dir/isolate_snapshot.bin",
-  ]
-  output = "$target_gen_dir/snapshot.c"
-  outputs = [
-    output,
-  ]
+  input = "$target_gen_dir/vm_isolate_snapshot.bin"
+  output = "$target_gen_dir/vm_snapshot_data.S"
+  symbol = "kDartVmSnapshotData"
+  executable = false
+}
 
-  script = "//dart/runtime/tools/create_snapshot_file.py"
-  args = [
-    "--vm_input_bin",
-    rebase_path("$target_gen_dir/vm_isolate_snapshot.bin"),
-    "--input_bin",
-    rebase_path("$target_gen_dir/isolate_snapshot.bin"),
-    "--input_cc",
-    rebase_path("snapshot.c.tmpl"),
-    "--output",
-    rebase_path(output),
+bin_to_assembly("vm_snapshot_instructions_assembly") {
+  deps = [
+    ":generate_snapshot_bin",
   ]
+  input = "$target_gen_dir/vm_snapshot_instructions.bin"
+  output = "$target_gen_dir/vm_snapshot_instructions.S"
+  symbol = "kDartVmSnapshotInstructions"
+  executable = true
+}
+
+bin_to_assembly("isolate_snapshot_data_assembly") {
+  deps = [
+    ":generate_snapshot_bin",
+  ]
+  input = "$target_gen_dir/isolate_snapshot.bin"
+  output = "$target_gen_dir/isolate_snapshot_data.S"
+  symbol = "kDartIsolateCoreSnapshotData"
+  executable = false
+}
+
+bin_to_assembly("isolate_snapshot_instructions_assembly") {
+  deps = [
+    ":generate_snapshot_bin",
+  ]
+  input = "$target_gen_dir/isolate_snapshot_instructions.bin"
+  output = "$target_gen_dir/isolate_snapshot_instructions.S"
+  symbol = "kDartIsolateCoreSnapshotInstructions"
+  executable = true
 }
 
 source_set("snapshot") {
-  sources = [
-    "$target_gen_dir/snapshot.c",
-  ]
-
   deps = [
-    ":generate_snapshot_file",
+    ":isolate_snapshot_data_assembly",
+    ":isolate_snapshot_instructions_assembly",
+    ":vm_snapshot_data_assembly",
+    ":vm_snapshot_instructions_assembly",
+  ]
+  sources = [
+    "$target_gen_dir/isolate_snapshot_data.S",
+    "$target_gen_dir/isolate_snapshot_instructions.S",
+    "$target_gen_dir/vm_snapshot_data.S",
+    "$target_gen_dir/vm_snapshot_instructions.S",
   ]
 }

engine/src/flutter/lib/snapshot/snapshot.c.tmpl

@@ -1,29 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <inttypes.h>
-#include <stdint.h>
-#include <stddef.h>
-
-// The string on the next line will be filled in with the contents of the
-// generated snapshot binary file for the vm isolate.
-// This string forms the content of the dart vm isolate snapshot which
-// is loaded into the vm isolate.
-const uint8_t kDartVmSnapshotData_[]
-    __attribute__((aligned(8))) = { %s };
-const uint8_t* kDartVmSnapshotData
-    __attribute__((visibility("default"), used)) = kDartVmSnapshotData_;
-const uint8_t* kDartVmSnapshotInstructions
-    __attribute__((visibility("default"), used)) = NULL;
-
-// The string on the next line will be filled in with the contents of the
-// generated snapshot binary file for a regular dart isolate.
-// This string forms the content of a regular dart isolate snapshot which
-// is loaded into an isolate when it is created.
-const uint8_t kDartIsolateCoreSnapshotData_[]
-    __attribute__((aligned(8))) = { %s };
-const uint8_t* kDartIsolateCoreSnapshotData
-    __attribute__((visibility("default"), used)) = kDartIsolateCoreSnapshotData_;
-const uint8_t* kDartIsolateCoreSnapshotInstructions
-    __attribute__((visibility("default"), used)) = NULL;

engine/src/flutter/lib/snapshot/snapshot.h

@@ -7,8 +7,8 @@
 #include <stdint.h>
 
 extern "C" {
-extern const uint8_t* kDartVmSnapshotData;
-extern const uint8_t* kDartVmSnapshotInstructions;
-extern const uint8_t* kDartIsolateCoreSnapshotData;
-extern const uint8_t* kDartIsolateCoreSnapshotInstructions;
+extern const uint8_t kDartVmSnapshotData[];
+extern const uint8_t kDartVmSnapshotInstructions[];
+extern const uint8_t kDartIsolateCoreSnapshotData[];
+extern const uint8_t kDartIsolateCoreSnapshotInstructions[];
 }